Great die-off 250 million years ago could trace in part to waters' change in pH

By Alexandra Witze, 17:18 PM September 2, 2011

The question of what killed most life on Earth 250 million years ago is a veritable Murder on the Orient Express, with multiple characters all dealing part of the deathblow. Now, scientists have learned how one of the assassins — acid — could have performed its part of the deed.

High levels of atmospheric carbon dioxide would have turned the oceans more than acidic enough to kill off marine critters, a computer simulation indicates.